Egberts J, Fontijne P, van der Weijden G C
Eur J Obstet Gynecol Reprod Biol. 1981 Jun;12(1):59-67. doi: 10.1016/0028-2243(81)90066-6.
The present study was conducted to monitor changes in surface activity of lung and amniotic fluid of premature lambs. Lung fluid was continuously obtained from 10 tracheotomized fetal lambs (gestational age 98-112 days) until (premature) parturition. Amniotic fluid was sampled twice a week from 3 other lambs by catheterization, and during cesarean section at the end of the gestational period from another 3 lambs. Surface activity in lung fluid increased on the first postoperative day, the more so when this occurred at a later fetal age in the period of 98-112 days. These findings show that even before day 110 'stress' can result in a release of surface active material. A return to low surface activity (about 26 mN/m) was observed within 3 to 6 days. Thereafter, between days 110 and 120, surface activity increased steeply within the individual animals but with large variability between the fetuses. The steep and premature increased was followed by a further but slow increase during the mature period and Ymin values of approximately 2 mN/m were reached. Amniotic fluid surface activity changed slowly with gestational age, but did not reach Ymin values of less than 15 mN/m. Lung fluid total phospholipid phosphorus values were low (about 6 micro M) up to 125 days, when they increased rapidly (greater than 16 micro M). Lung fluid production increased from 4.9 ml/h at the beginning of the experiment to 12.1 ml/h after day 130 but decreased dramatically 1-3 days before (premature) parturition. Experiments on fetal lung maturation should be started before day 105 of gestation and we suggest that measurement of surface activity of fetal lung fluid may be useful in monitoring changes in the premature alveolar type II cells of lambs.
本研究旨在监测早产羔羊肺和羊水表面活性的变化。通过气管切开术，从10只胎羊（胎龄98 - 112天）持续获取肺液直至（早产）分娩。另外3只羊每周通过导管插入术采集两次羊水样本，在妊娠期结束时剖宫产时，从另外3只羊采集羊水样本。术后第一天肺液表面活性增加，在98 - 112天这个胎龄阶段后期发生时增加得更明显。这些发现表明，甚至在第110天之前，“应激”就能导致表面活性物质的释放。在3至6天内观察到表面活性恢复到低水平（约26 mN/m）。此后，在第110天至120天之间，个体动物的表面活性急剧增加，但胎儿之间差异很大。急剧且过早的增加之后，在成熟阶段进一步缓慢增加，达到约2 mN/m的Ymin值。羊水表面活性随胎龄缓慢变化，但未达到低于15 mN/m的Ymin值。肺液总磷脂磷值在125天之前较低（约6微摩尔），之后迅速增加（大于16微摩尔）。肺液生成从实验开始时的4.9毫升/小时增加到第130天后的12.1毫升/小时，但在（早产）分娩前1 - 3天急剧下降。胎儿肺成熟实验应在妊娠第105天之前开始，我们建议测量胎儿肺液的表面活性可能有助于监测早产羔羊肺泡II型细胞的变化。
